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Author Topic: LED Dimmer pack? Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 09-14-2013 02:24 PM                     A cinema has decided to save electrical cost by installing LED replacement lamps in all house lighting fixtures. After that they discovered the existing dimmers won't dim them, they are "dimmable" lamps but the dimmer is not compatible. The dimmer manufacturer agrees and says the unit can not be made compatible. Has anyone found a dimmer pack that works with these lamps? We need dry contact, serial, or ethernet control with 3 presets (feature off, trailer/credits dim, exit full). Load power is about 300W with the LED lamps but having a higher load rating won't hurt. Thanks in advance!  |  IP: Logged Steve Moore Expert Film Handler Posts: 211 From: Leeds, West Yorks, UK Registered: Apr 2008 posted 09-14-2013 02:46 PM                     If anyone has I'd love to know too, been looking for this for ages. Currently I use 20 x 100w lamps over my screen curtains and am struggling to find LEDs with a long enough throw too. I have looked into getting a DMX controller for them then buying a analog 0-10v interface and borrowing a couple of the channel feeds that come from the dimmer controls to the dimmer pack as a method, thus still the same controls in the projection room. (something like one of these http://northlightdmx.com/dmx512decoder.htm )  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 09-14-2013 06:14 PM                     LED fixtures are quickly taking over in the live theater world and many of those dimmer racks are compatible with LED so it's probably just a short time till theater light dimmers make the required changes to bring compatability around.  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 09-14-2013 11:56 PM                        I wonder if these would work if one of the lamps remained incandescent. Triac and SCR dimmers have trouble with nonlinear loads. Harold Used to design dimmers for http://www.dovesystems.com .  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 09-15-2013 01:41 PM                     Harold...at the AFI/Silver, they have Lutron dimmers. And yes, by leaving one incandescent in the load of each bank...LED dimming seems to work perfectly. -Steve  |  IP: Logged Mark Hajducki Jedi Master Film Handler Posts: 500 From: Edinburgh, UK Registered: May 2003 posted 09-15-2013 03:33 PM                     I have seen theatre lighting dimmers dislike low loads (such as filament Christmas lights) once a traditional lantern was connected in parallel there was no problem.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 09-15-2013 04:32 PM                     I believe you will find that most any dimmer that utilizes a solid state relay instead of a triac or dual scr will work. So checking which dimmers utilize this sort of load transfer device should be easy to find out. This link may also help you out... Phillips LED Lamp Dimmer Reccomendations This article may also be helpful Understanding Dimmer Compatability & Wiring Issues  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 09-15-2013 08:29 PM                     Steve, what happens when that incandescent bulb dies? Does it cause any damage to the dimmer? I would assume the LEDs no longer dim properly.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 09-16-2013 06:09 AM                     The load seems like it doesn't dim....and then just goes out. It is like having a delayed switch rather than a dimmer.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 09-16-2013 12:06 PM                     A triac SCR or SSR block all exhibit one issue in that the current and voltage must be in phase with each other or it will not be stable Inductive loads or capacitance loads often cause them to either not have a suitable dimming range or that they flicker Some transformer loads the transformer will fail to saturate on turn on at low levels and damage the thyristor We usually put a large power resistor in serries with transformer LV lamps to minamize inrush and put a snubbing cap across the load to correct power factor Some LED lights use a solidstate powersupply and they will dislike any chopped wave form  |  IP: Logged

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